Caesar did not himself report in any of his works that he uttered these famous words. But Suetonius does:

In English:

While he was thus hesitating, the following incident occurred. A person remarkable for his noble mien and graceful aspect, appeared close at hand, sitting and playing upon a pipe. When, not only the shepherds, but a number of soldiers also flocked from their posts to listen to him, and some trumpeters among them, he snatched a trumpet from one of them, ran to the river with it, and sounding the advance with a piercing blast, crossed to the other side. Upon this, Caesar exclaimed, " Let us go where the omens of the Gods and the iniquity of our enemies call us. The die is now cast."

I also learned the latin phrase as being "alea iacta est" (in that order). One of my university teachers slapped me on the fingers once however, because he insisted I should use "alea iacta sit", since that would be the better translation from the Greek original.

Lucus Eques wrote:What in the Suetonius quote suggests that he should have said that phrase in Greek?

IIRC it was fashionable for the Roman aristocracy of the time to speak Greek. Again IIRC (Suetonius again?) Caesar's final words to Brutus were "Kai su teknon ?", not the better known "Et tu, Brute ?".

I doubt that though, as his final words were directed at the senators, to whom he would have spoken in Greek, but it seems unlikely that he would have used these famous words in Greek when they were directed at his soldiers (this is supported by Suetonius who quotes his last words in Greek and these in Latin).

when dealing with Suetonius' quotations it's worth noting or at least being aware of the importance of whom he quotes from. if it's something anecdotical, or fellow biographers' works, Greek would be allowed; if from historians Greek would be translated. so something may come to us as Latin (jacta alea est) but be really original Greek (although I do agree with catfish that his audience at the incident makes that unlikely).

Hesperado:
what we now write as "v" served variably regarding different graphemes and different writing arbitrarinesses. however, in classical times, during which Caesar lived, both what we now write as "u" and what we write "v" were pronounced "u".

Indeed, Classical Latin 'v' is pronounced as English 'w', while German 'v', for the sake of contrast, is pronounced as English 'f'. It's not limp at all if you pronounce the sounds with their full, Italic quality, and not merely as if they were as English "wenee, weedee, weekee."